Spend your money on a real fitness watch like Suunto or Garmin. It will be a better investment for the OP.
I have to disagree on that! I have a Garmin 610 and 620 and since I got the Apple Watch my Garmin has been on rocky ground. In fact this morning I was considering eBay'ing it.
Once native apps turn up with training calendars and interval training (and they will) my Garmin will be history. For £350 you can get a smartwatch that does pretty much everything a £370 Garmin 620 does, apart from having integrated GPS (and some gimmicky run metrics like vertical oscillation and ground impact time). If you run with your phone anyway (most do) the Garmin offers very little.
People talk about sportwatches like they run on magic. They are just watches with GPS, accelerometers and a pretty clunky and outdated UI that rarely gets updated and never changes it functionality. Their days are numbered.